1. Field of the Invention
The present invention relates generally to a pneumatic tool, and more particularly to an innovative tool to adjust the torsional force by switching a plurality of a plurality of exhaust holes.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
The pneumatic tools are generally used in such a manner that the torsional force has to be adjusted depending on the targets. The torsional force of conventional pneumatic tool is generally changed by adjusting the rotational speed of rotor through air intake regulating mechanism.
However, while external air is guided into the drive rotor of the cylinder of the pneumatic tool, the same squeezing stroke shall be required to make the air reach the exhaust hole of the cylinder. When air intake increases, the rotational speed and torsional force of the rotor cannot rise obviously due to the limitation of the fixed guiding and exhaust stroke. In such a case, the torsional force of conventional pneumatic tool cannot be improved or adjusted actually.
In addition, another typical structure has been developed in this industry, namely, with the forward offset of the exhaust hole of the cylinder. A shorter squeezing stroke for the guided air can be realized for a proper positive rotational torsion and a bigger reverse rotational torsion, but some shortcomings still exist, e.g. lack of adjustment flexibility in meeting the diversified customer requirements.
Thus, to overcome the aforementioned problems of the prior art, it would be an advancement in the art to provide an improved structure that can significantly improve efficacy.
Therefore, the inventor has provided the present invention of practicability after deliberate design and evaluation based on years of experience in the production, development and design of related products.